Reputation: 100
I am having some trouble to compile a code using shared libraries on MacOSX. I first wrote it on Debian before trying to compile it on MacOSX.
Here is the code:
test.hxx:
#ifndef TEST_HXX
#define TEST_HXX
namespace test
{
class CFoo
{
/* data */
public:
CFoo (){}
virtual ~CFoo (){}
void bar();
}; /* CFoo */
} /* namespace test */
#endif /* TEST_HXX */
test.cxx:
#include <iostream>
#include "test.hxx"
void test::CFoo::bar()
{
std::cout << "Hello world!" << std::endl;
} /* bar() */
other.hxx:
#ifndef OTHER_HXX
#define OTHER_HXX
namespace other
{
class CBar
{
public:
CBar (){}
virtual ~CBar (){}
void foo();
}; /* CBar */
} /* namespace other */
#endif /* OTHER_HXX */
other.cxx:
#include <iostream>
#include "test.hxx"
#include "other.hxx"
void other::CBar::foo()
{
test::CFoo c;
c.bar();
} /* bar() */
main.cxx:
#include "other.hxx"
int main (int argc, const char *argv[])
{
other::CBar c;
c.foo();
return 0;
} /* main () */
And a simple makefile:
LIBTEST = libtest.so
LIBOTHER = libother.so
all: $(LIBTEST) $(LIBOTHER)
g++ -ltest -lother -I. -L. main.cxx
libtest.so: test.o
g++ -shared test.o -o $(LIBTEST)
libother.so: other.o
g++ -shared other.o -o $(LIBOTHER)
test.o: test.cxx test.hxx
g++ -fPIC -c test.cxx
other.o: other.cxx other.hxx
g++ -fPIC -c other.cxx
clean:
$(RM) $(LIBOTHER) $(LIBTEST) test.o other.o a.out
So I basically create objects test.o
and other.o
and create two shared libraries from them (one per object).
other.cxx
uses the class contained in test.cxx
to print Hello world
.
So this makefile and the code works fine on my Debian but I have a compilation error when trying to compile it on MacOSX:
g++ -fPIC -c test.cxx
g++ -shared test.o -o libtest.so
g++ -fPIC -c other.cxx
g++ -shared other.o -o libother.so
Undefined symbols for architecture x86_64:
"test::CFoo::bar()", referenced from:
other::CBar::foo() in other.o
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [libother.so] Error 1
It compiles and creates my shared library for test
but fails when creating libother.so
.
When using only one shared library (so printing Hello world
in main
directly from test
) it works just fine but the problem occurs when using several shared libraries...
I am not an Apple user and never works on MacOSX before so I don't really understand how linking is being done. And the error doesn't really makes sense to me...
Thank you for helping me to understand this error!
Upvotes: 3
Views: 2147
Reputation: 1449
This is because libother
uses libtest
but you don't link with it. Try
g++ -shared other.o -o libother.so -L. -ltest
The -L
tells the compiler where to search for the library, -l
links with it.
Upvotes: 6